Merge branch 'tb/log-G-binary'

"git log -G<regex>" looked for a hunk in the "git log -p" patch
output that contained a string that matches the given pattern.
Optimize this code to ignore binary files, which by default will
not show any hunk that would match any pattern (unless textconv or
the --text option is in effect, that is).

* tb/log-G-binary:
  log -G: ignore binary files

Documentation/diff-options.txt

@@ -524,6 +524,8 @@ struct), and want to know the history of that block since it first
 came into being: use the feature iteratively to feed the interesting
 block in the preimage back into `-S`, and keep going until you get the
 very first version of the block.
++
+Binary files are searched as well.
 
 -G<regex>::
 	Look for differences whose patch text contains added/removed
@@ -543,6 +545,9 @@ While `git log -G"regexec\(regexp"` will show this commit, `git log
 -S"regexec\(regexp" --pickaxe-regex` will not (because the number of
 occurrences of that string did not change).
 +
+Unless `--text` is supplied patches of binary files without a textconv
+filter will be ignored.
++
 See the 'pickaxe' entry in linkgit:gitdiffcore[7] for more
 information.
 

Documentation/gitdiffcore.txt

@@ -242,7 +242,8 @@ textual diff has an added or a deleted line that matches the given
 regular expression.  This means that it will detect in-file (or what
 rename-detection considers the same file) moves, which is noise.  The
 implementation runs diff twice and greps, and this can be quite
-expensive.
+expensive.  To speed things up binary files without textconv filters
+will be ignored.
 
 When `-S` or `-G` are used without `--pickaxe-all`, only filepairs
 that match their respective criterion are kept in the output.  When